The Cloud of Unknowing, ed. by Evelyn Underhill, , at sacred-texts.com
That a man should bidingly travail in this work, and suffer the pain thereof, and judge no man.
AND therefore, whoso coveteth to come to cleanness that he lost for sin, and to win to that well‑being where all woe wanteth, him behoveth bidingly to travail in this work, and suffer the pain thereof, whatsoever that he be: whether he have been an accustomed sinner or none.
All men have travail in this work; both sinners, and innocents that never sinned greatly. But far greater travail have those that have been sinners than they that have been none; and that is great reason. Nevertheless, ofttimes it befalleth that some that have been p. 170 horrible and accustomed sinners come sooner to the perfection of this work than those that have been none. And this is the merciful miracle of our Lord, that so specially giveth His grace, to the wondering of all this world. Now truly I hope that on Doomsday it shall be fair, when that God shall be seen clearly and all His gifts. Then shall some that now be despised and set at little or nought as common sinners, and peradventure some that now be horrible sinners, sit full seemly with saints in His sight: when some of those that seem now full holy and be worshipped of men as angels, and some of those yet peradventure, that never yet sinned deadly, shall sit full sorry amongst hell caves.
Hereby mayest thou see that no man should be judged of other here in this life, for good nor for evil that they do. Nevertheless deeds may lawfully be judged, but not the man, whether they be good or evil. p. 171